Circadian clocks enable organisms to keep track of the time of day and to adjust their physiology to recurring, and therefore predictable, daily changes in the external environment. Our work has demonstrated that circadian clocks are critical regulators of mammalian metabolic physiology and the response to DNA damage. We are studying the molecular basis for the circadian control of metabolism, DNA damage response, and tumorigenesis to enable novel therapies to treat metabolic disease and cancer.